Chemical Mechanical Polishing (CMP) systems are widely used in the integrated circuit manufacturing industry to produce very smooth surfaces upon which integrated circuits may be assembled. The CMP systems typically use an aqueous slurry solution containing a chemical corrosive together with abrasive particles that accelerate the effectiveness of the chemical corrosive. The abrasive particles can contaminate slurry distribution systems by agglomerating into larger particles and clogging the plumbing of the slurry distribution system, and by building up on the surfaces of the plumbing or the tank of the slurry distribution system. This not only impedes the desired circulation of the slurry solution, but also creates fluctuations in the concentration and size of the abrasive particles in the slurry solution, causing manufacturing problems such as scratching of the wafer surfaces or deposits of the abrasive particles on the wafer surfaces being polished. Therefore, these systems must be frequently cleaned to rid the systems of buildup of these abrasive particles.
The cleaning processes currently utilized typically create significant inefficiencies. Some cleaning methods require that the entire system be drained and filled with a cleaning solution designed to rid the system of deposits of the abrasive particles. The operator must first stop production, drain the system of the slurry solution, and run the cleaning solution through the slurry distribution system until the particulate buildup has been sufficiently removed. It is important to maintain the pH of the aqueous slurry solution and the concentration of abrasive particles within a very small range in order to minimize scratches and deposits of abrasive particles on the wafer surfaces. Therefore, because the cleaning solutions frequently contain chemicals which are not typically present in the slurry solution, the system must then be thoroughly flushed in order to rid the system of any chemicals which might cause fluctuations in the composition of the slurry solution. These systems for cleaning the slurry distribution system are not desirable because they create considerable downtime and consume large amounts of chemicals which may be expensive and difficult to properly dispose.
Other cleaning methods require disassembly of the slurry distribution system in order to individually clean the plumbing components of deposits of the abrasive particles. The user must stop production, completely drain the system of the slurry solution, and disassemble the plumbing of the slurry distribution system. The plumbing components must then be individually cleaned of the particle buildup, reassembled, and the system re-filled with the slurry solution before production may resume. This system is also not desirable in that it requires significant downtime.
Accordingly, there is a need for more efficient methods of cleaning CMP slurry distribution systems.